High speed returning impact forming machine



Feb. 18, 1969 AK|RA s l 3,427,356

HIGH SPEED RETURNING IMPACT FORMING MACHINE Filed March 9, 1967 Sheet of8 (Rom held upwords) m INVENTOR.

Feb. 18, 1969 AKIRA ASARI 3,427,856

. HIGH SPEED RETURNING IMPACT FORMING MACHINE Filed March 9, 1967 Sheet2 of s (Forming) v INVENTOR.

Feb. 18, 1969 AKlRA ASARI 3,

HIGH SPEED RETURNING IMPACT FORMING MACHINE Filed March 9,1967 Sheet 3of (Ram on The way upwards) INVENTOR.

BY ad/ W Feb. 18, 1969 AKIRA ASARI 3,427,355

HIGH SPEED RETURNING IMPACT FORMING MACHINE Filed March 9, 1967 Sheet 4of 1 lOdlOb"

/ lOb" 1| miummrm u u v (Rom returned completely) 04010 INVENTOR.

Emma 524 Feb, 18, 1969 AKIRA' ASARI 3, ,35

HIGH SPEED RETURNING IMPACT FORMING MACHINE Filed March 9, 1967 Sheet 5of 8 lOc (Crank uppermosr) Y INVENTOR.

Fb. 18, 1969 AKIRA ASARI 3,427,355

HIGH SPEED RETURNING IMPACT FORMING MACHINE Filed Harsh 9. 1967 Sheet 6of (Frame descended completely) INVENTOR.

Feb. 18, 1969 AKIRA ASARI 3,427,356

HIGH SPEED RETURNING IMPACT FORMING MACHINE Filed March 9, 1967 Sheet 7of s Cronkfl2) Rum Supporfing (10) LVGlve (7) Movable Frame BYLUMM Feb.18, 1969 I AKIRA ASARI 3,427,856

HIGH SPEED RETURNING IMPACT FORMING MACHINE Filed March 9, 1967 Sheet 8of a IOd I Y 1AM United States Patent 3,427,856 HIGH SPEED RETURNINGIMPACT FORMING MACHINE Akira Asari, Osaka-shi, Japan, assignor to KobeSteel Ltd., Fukiai-ku, Kobe, Japan Filed Mar. 9, 1967, Ser. No. 621,940Claims priority, application Japan, Mar. 14, 1966,

41/ 16,048 US. Cl. 72-450 8 Claims Int. Cl. B21j 9/18, B30b 1/32ABSTRACT OF THE DISCLOSURE Cross reference to related applicationReference is made to US. patent applications of Akira Asari entitled,High Energy Rate Forming Machine, Ser. No. 384,103, filed July 21, 1964,now Patent No. 3,354,693; Method for Operating the Ram in an ImpactProcessing Machine and a Device for Carrying Out Said Method, Ser. No.564,681, filed July 12, 1966; and A Knock-Out Device of Impact FormingMachine, Ser. No. 574,033, filed Aug. 22, 1966.

Background of the invention This invention relates to a high speedreturning impact forming machine in which gas pressure is utilized as asource of power for driving its ram, and more particularly is directedto an impact forming machine in which a mechanical force is used forreturning a ram in high speed and hydraulic pressure stopper means areadopted for returning the ram in safety supporting.

It has been found that an impact forming machine deforms variousmaterials by using the velocity energy by means of a high speed of ramand a very large force can be obtained by this and furthermore, it hasthe feature of having a very high fabrication speed.

Machine for using gas pressure is preferred t machine for utilizing amechanical force in order to supply high speed energy to a ram so thatthe ram is forced in extremely high speed. For driving the ram by usinggas pressure, there are various ways for using the gas pressure fordriving the ram, but the common manner is such that the ram is drivendownwards in a very high speed by receiving gas pressure on the uppersurface of the ram, whereby the desired forming work is done in a metalmould provided on the machine.

In such an operation, since the impact force of the ram is great amount,which effects a great deal of shock and vibration on the ground, themoving frame of this machine for operating the ram is supported througha cushion such as an air spring so that it is laterally movable up anddown. However, if the frame is supported so as to move laterally, whenthe ram is returned back upwards by means of a jacking mechanism securedto the fixed frame after its descent has completed to operate its impactforming, the movable frame tends to move upwards 3,427,856 Patented Feb.18, 1969 together with the ram. Accordingly, the impact formed productin the metal mould is delayed to separate therefrom, causing bad effectthereto. Furthermore, the relative motion between the ram and themovable frame is effected to be inaccurate, thereby becoming verydiflicult to set the operating time of the valve for controlling theoperation of the ram so as to communicate between the high pressurechamber and the upper portion of the cylinder for receiving the plungerintegral to the ram.

Further, when the ram is in a state that it initiates to return to itsuppermost position after impact forming operation, since the highpressure in the gas pressure member operates so that it pushes upwardsthe movable frame, if there is no stopping means for stopping themovable frame, the frame moves upwards together with the ram so that themetal moulds may not separate each other. If the stopper means securedto the fixed frame stop from the first the upward movement of themovable frame even if the upward motion of the movable frame is adaptedto be prevented by a part or stopper means of the fixed frame, thereaction of the movable frame is impossible to be effected in the impactforming operation. Or, if the space between the movable frame and thestopper means secured to the fixed frame is predetermined to beprovided, the reaction of the movable frame is allowed, however whilstthe stroke from that the ram initiates to return upwards to itsuppermost position after its impact forming operation to that themovable frame raises upwards so as to contact with the stopper meanssecured to the fixed frame is done, the movable frame moves furtherupwards together with the ram, between which the metal mould is held incontact each other.

Assuming that the valve for communicating between the gas pressurechamber and the upper portion of the cylinder for receiving the plungerintegral to the ram is open or is not closed completely immediatelyafter the ram reaches its initial uppermost position so as to lower thesupporting member, the high pressure of the chamber flown back throughthe conduits and the valve effects to actuate upon the upper surface ofthe plunger so that it initiates to descend the ram accidentally causingits dangerous operation. However, when the supporting member of the ramreciprocates up and down by means of a mechanical force such as thecrank, it moves downwards or in such a direction that it separates fromthe ram immediately after it reaches its initial uppermost positions sothat it removes the supporting operation of the ram. Accordingly, thevalve must be closed immediately after the supporting member reaches itsuppermost position.

If the valve closes before the ram reaches its uppermost position, thegas enclosed in the cylinder cannot return through the conduits and thevalve to the chamber. Furthermore, the plunger of the ram is not yetreached to its uppermost position or its inner uppermost position,accordingly the compression occurs in the cylinder by the plunger. Also,if the valve closes in some delay after the ram arrives at its uppermostposition, the gas flown back through the conduits and the valve initiateto operate accidentally the ram, since the supporting member initiatesto descend before the valve closes.

Summary of the inventi n This invention eliminates the above mentioneddisadvantages of the conventional impact forming machine and provides anovel high speed returning impact forming machine in which an impactforming operation is shortened by using the mechanism for convertingrotational motion to a reciprocating movement upon returning the ram tothe initial uppermost position after it has performed the impact formingoperation, and also when the ram returns upwards to its initialuppermost position the metal moulds separate immediately each other byadopting the hydraulic pressure stopper means disposed above the movableframe and secured to the fixed frame.

The principle of the present invention, which will be hereinafterdescribed, is that in the high speed returning impact forming machineprovided with a movable frame supported by means of cushion a returningmotion of the movable frame is restricted. That is, the reaction of themovable frame is allowed in its impact forming opera tion, however whenthe ram initiates to return upwards to its uppermost positionimmediately after its impact forming operation, the movable frame isprevented to raise upwards together with the ram, and only ram ispermitted to return upwards to its uppermost position so as to effect toseparate the impact formed product from the metal mould immediately.Further, in the impact forming machine in which after its impact formingoperation the ram is returned upwards to its initial uppermost positionby means of mechanical jacking mechanism such as a crank mechanism, theram is returned upwards integrally with the movable frame in some strokeeven after it reaches its uppermost position relative to the movableframe, thereby the time for enabling to control the valve forcommunicating the high pressure from the gas pressure chamber to theupper portion of the cylinder for operating the ram, is effected tolengthen. More particularly, the ram operated by the high pressure inthe chamber is supported or held by the movable frame supported by meansof the cushion, and in order to return the ram to its initial uppermostposition the jacking mechanism secured to the fixed frame is utilized soas to enable lateral movement up and down relative to the movable frameor the stopper means are provided. This stopper means is, for example,comprised of a piston and cylinder in combination. It is adapted todrive the piston by means of hydraulic pressure. The stopper means allowits reaction of the movable frame in its impact forming operation tooperate, however in the returning stroke of the ram after its impactforming operation it does not permit its returning movement of themovable frame together with the upward movement of the ram. On the otherhand, the stopper means have a cushioning function against the jackingmechanism in the returning stroke to the uppermost position of thejacking mechanism after the ram returned to the uppermost position inthe movable frame. And for the cushioning of the stopper means againstthe jacking mechanism another cushioning means or hydraulic pressuremeans may be used.

One advantage of this invention is referred to the stopper means whichis disposed fixedly to the upper portion of the fixed frame and whichcomprises hydraulic pressure cylinder disposed fixedly downwards to theframe, stopper pistons being inserted to the cylinder, and rods adaptedto be integral to the piston, the rods being projected downwards anddisposed opposite to the upper surface of the movable frame, therebyenabling to stop the movable frame moving upwards. It is operated sothat when the ram returns upwards metal moulds separate immediately eachother so as to pick up easily the impact formed products. The piston ofthe stopper means is adapted to be capable of laterally moving upwardsand downwards by applying hydraulic pressure from the upper or lowerportion thereof. And the stopper means are so disposed that the distancebetween the lowermost portion of the rods and the uppermost of themovable frame balanced with the cushion is larger than the boundedheight of the movable frame from the normal level caused by the reactionof the ram descended. Thus, it provides the cushioning function with itsinitial stopping operation.

It is another advantage of this invention that the stopper piston of thestopper means is adapted to be disposed at its lowermost positionimmediately before the supporting member initiates to contact the headof the stem on the way moving from its lowermost position, and it isdisposed so that when the plunger of the ram reaches its uppermostposition in the cylinder the crank enable to raise further integrallywith the supporting member together with the ram on opposing to thehydraulic pressure in upper portion of the stopper means in its restedstroke. Thus, only the ram returns upwards to its initial uppermostposition and the impact formed products are separated from the metalmould.

Yet another advantage of this invention is seen in that for a littlewhile from the middle until the crank reaches its uppermost position,the crank is allowed to raise further in a state that the ram holds inits uppermost position. Therebetween, the crank initiates its downstroke. Thus, even if the ram is not held in its uppermost position, thehigh pressure gas in the chamber is not permitted to flow back throughthe conduits and the valve so as to effect upon the upper surface of theplunger so that the ram may not be operated accidentally to descenddownwards to operate its impact forming.

=Therefore, one object of this invention is to provide a high speedreturning impact forming machine in which when the ram returns to itsuppermost position it is safely and positively supported.

Another object of this invention is to provide a high speed returningimpact forming machine in which metal moulds separate easily andimmediately each other when the ram returns upwards to its uppermostposition.

A still further object of this invention is to provide a high speedreturning impact forming machine in which in the returning stroke of theram the movable frame may not be permitted to move upwards with theupwards movement of the ram.

Still another object of this invention is to provide a high speedreturning impact forming machine in which the reaction of the movableframe when the ram operates its impact forming is allowed and furtherwhen it returns only the frame is restricted to raise.

Still another object is to provide a high speed returning impact formingmachine which has a cushioning function together with stopping operationof the movable frame when the ram returns upwards.

Still another object is to provide a high speed returning impact formingmachine in which a great impact force by the ram is cushioned.

A further object of this invention is to provide a high speed returningimpact forming machine in which the valve for communicating the highpressure in the gas pressure chamber to the upper portion of thecylinder for operating the ram, is controlled smoothly to open or close.

Still another object of this invention is to provide a high speedreturning impact forming machine in which drawback in the cylinder isremoved.

This invention provides a high speed returning impact forming machineemploying gas pressure means in which machine a mechanism for convertingthe rotary motion to linear reciprocating movement is provided, by whichmechanism the linear motion converted from the rotating movement isadapted to correspond to the driving direction of the ram, and thereciprocating motion thereof is transmitted to the returning member orthe ram supporting member, thereby the ram is returned to its initialuppermost position through the member to which the extended portionupwards integrally from the top of the ram or a stem is hung. Thus, theimpact forming machine in accordance with this invention is providedsuch that the ram is returned to its initial uppermost position by meansof linear motion of the aforementioned mechanism such as a crankmechanism in high velocity after the impact forming operation has done,accordingly the impact forming cycle is shortened in great amount. Inaddition, the cycle is made continuous operation and the efficiency ofthe operation is extremely improved in impact formation of the machinein accordance with this invention.

Furthermore, this invention provides a novel and improved high speedreturning impact forming machine wherein part of the mechanical force,by which the ram is returned to its initial uppermost position by meanssuch as the crank mechanism, is used in the operation for opening orclosing a control valve of a ram driving gas pressure, thereby enablingthe coo-peration with the actuation of the ram and the furtherrationalization of the operational program in the impact forming machineaccording to this invention.

In order to hold the ram returned to its initial uppermost position safebecause of its importance so as to avoid the accidental operation of theram in improper time when the ram is raised to its uppermost levelcaused by the adoption of the mechanical force to return the ram to itsinitial uppermost position, this invention also provides a high speedreturning impact forming machine in which hydraulic pressure means areprovided and which comprises a piston provided on the top of means fordriving the ram supporting member, a cylinder for receiving the pistonprovided on the lowermost portion of the member, communications boredlongitudinally along with the member, and conduits for connecting theends of the communication and source of the hydraulic pressure, and isdisposed between the top of the crank mechanism and the lowermostportion of the supporting member, thereby operating so that the crankmechanism for driving the supporting member move further upwards to thetop during a little while after the ram integral to the supportingmember has reached. Thus, this invention eliminates the drawback in thecylinder received by the plunger integral to the ram and the accidentaldescent of the ram.

Further, this invention also provides the impact forming machine inwhich the reaction of the movable frame is allowed in its formingoperation, but when the ram initiates to return upwards to its uppermostposition immediately after its impact forming operation, the movableframe is prevented to raise upwards together with the ram, and only ramis permitted to returnupwards to its uppermost position so as to effectto separate the impact forming machine in which after its impact formingoperation the ram is returned upwards to its initial uppermost positionby means of mechanical jacking mechanism such as a crank mechanism, theram is returned upwards integrally with the movable frame, thereby thetime for enabling to control the valve for communicating the highpressure from the gas pressure chamber to the upper portion of thecylinder for operating the ram, is effected to lengthen.

This invention provides also a high speed returning impact formingmachine in which the ram operated by the high pressure in the chamber issupported or held by the movable frame supported by means of thecushion, and in order to return the ram to its initial uppermostposition the jacking mechanism secured to the fixed frame is utilized soas to enable lateral movement upwards and downwards relative to themovable frame or the stopper means are provided. These stopper means arecomprised of a piston and cylinder in combination, which means areadapted to drive the piston by means of hydraulic pressure, and allowits reaction of the movable frame in its impact forming operation tooperate, but in the returning stroke of the ram after its impact formingoperation it does not permit its returning movement of the movable frametogether with the upward movement of the ram.

Other objects and advantages of this invention will further becomeapparent hereinafter, and from the drawings.

Brief description of the drawings FIGS. 1 through 6 are sectional sideelevations of a high speed returning impact forming machine constructedin accordance with a preferred embodiment of the present inventionshowing in its operational order;

FIG. 7 is an explanatory graph of operational curve of respective partsin impact forming operation; and

FIG. 8 is a sectional side elevation of another embodiment of a highspeed returning impact forming machine of this invention.

Description of the preferred embodiment Although specific forms of theinvention have been selected for illustration in the drawings, and thefollowing description is drawn in specific terms for the purpose ofdescribing those forms of the invention, this description is notintended to limit the scope of the invention, which is defined in theclaims.

Referring now to the drawings, and particularly to FIGS. 1, 2, 3, 4, 5and 6, a high speed returning impact forming machine comprises a gaspressure chamber 1 containing high pressure gas charged therein, a ram 2adapted to pass into the interior of the chamber from the bottom wallthereof, a plunger 3 formed on the uppermost end of the ram 2, acylinder 4 constructed inside the uppermost wall of the chamber 1 so asto receive the plunger 3, conduits 5 and 6 connected between the upperportion of the chamber 1 and the uppermost portion of the cylinder 4through a valve 7, a rod 8 projecting vertically upwards from theplunger 3 integrally for supporting the ram 2 by hanging a head 9 formedon the top of the rod 8 through a ram supporting member or moving frame10 so that the rod 8 communicates through an opening 11 for the head 9so as to be through above the opening 11, the diameter of the head 9being larger than that of the opening 11, so as to hang the ram 2integral with the rod 8, movable frame 10a disposed inside guides 10b offixed frame 10c, said movable frame being adapted to be laterallymovable up and down, and being supported by means of cushion 26 disposedunder the lowermost of the movable frame and station of this machine. Acrank shaft 12 driven by any conventional source of power (not shown),in the embodiment shown in the drawings two crank shafts being disposedso as to drive the ram supporting member 10 from opposite sides,respectively, two connecting rods 13 connected to the crank shaft 12 atrespective ends, thereby when the crank shafts are driven the supportingmember 10 moves reciprocally upwards and downwards in response to therotation of the shaft 12 through the connecting rods 13.

In the drawings, in operation of the impact forming machine, since highpressure gas is enclosed inside the gas pressure chamber 1, the plunger3 is pressed to the uppermost position of the cylinder 4 when the ram 2is disposed in the upper position so that the ram 2 is held in upperlever by the effect of the pressure in the chamber 1 to the lowersurface thereof. Furthermore, when the ram 2 is initiated to lowerdownwards by flowing the high pressure gas in the chamber 1 throughtheconduits 5 and 6, and the valve 7 into the upper portion of the cylinder4 so that the upper surface of the plunger 3 falls downwards lower thanthe lower surface of the cylinder 4, the pressure of the chamber 1effects immediately upon the upper surface of the plunger 3 so as tolower the ram 2 in very high speed, thereby forming the material in themould in the impact forming machine. And, the ram 2 once lowered asmentioned above is forced so as to be lifted back upwards when the crank12 is revolved further so as to raise the ram 2 through the connectingrods 13 and the rod 8 integral to the head 9 thereupon, the ramsupporting member 10, so that the supporting member 10 hangs up the head9 through the opening 11 of the supporting member 10. Since thecompression is produced in the cylinder 4 when the ram 2 is returnedupwards, immediately after the plunger 3 is inserted into the cylinder4, this compressed gas must be flown back to the pressure chamber 1through the conduits 6 and 5 and the valve 7. The supporting member isso constructed that from opposite ends supporting rods 10d, 10d isprojecting downwards, respectively, which rods are disposed laterallyslidably inside guides 10b, 10b of fixed frame 100 and connected to thetop of the connecting rods 13 of the crank 12 so as to be driven. Therotating shaft 27 for driving the crank 12 is connected through sets ofgears 23 and 24, rotating shaft 22, cam 20 and valve stem 21 to thevalve 7.

At the upper portion of the fixed frame 10b over the movable frame 10ais laterally secured hydraulic pressure stopper means 15, 15 whichcomprise hydraulic pressure cylinder 16 disposed fixedly downwards tothe upper portion of the fixed frame 10b, stopper piston 17 beinginserted to the cylinder, and rod 14 adapted to be integral to thepiston 17, the rods being projected downwards and disposed opposite tothe upper surface of the movable frame 10a, thereby enabling to stop themovable frame 10a moving upwards. The pistons 17 of the stopper meansare adapted to be able to laterally move upwards and downwards byapplying hydraulic pressure from the upper or lower portion of thecylinder. The lateral stroke L of the piston 17 is required, as will bedescribed hereinafter, so that the piston enables to press down themovable frame 10a sufficiently in order that the movable frame disposedat its normal level may not move upwards. This combination of thestopper piston 17 and the hydraulic pressure cylinder 16 forms stoppermechanism together with cushioning function.

In FIG. 1 illustrates the state immediately before the impact formingmachine initiate to form its operation in which state a movable frame10a is balanced at the normal position (designated by line A in FIG. 7)between the weight itself and a cushion 26. The ram 2 is held at theuppermost position by the high pressure of the gas in the chamber 1which pressure is acted on the lower surface of the plunger 3 (ram keptupwards in FIG. 1, and designated by numeral I in FIG. 7). At this time,the stopper piston 17 is disposed at its uppermost position (line B inFIG. 7) and is held by the hydraulic pressure by the crank 12 the ramsupporting member 10 is just on the way to fall downwards. The valve 7is, of course, close (illustrated by line C in FIG. 7). At that time, acam 20 is adapted to push upwards a valve stem 21 of the valve 7 so asto open the valve 7 (designated by numeral in position in FIG. 7),thereby the high pressure gas in the chamber 1 is introduced to theupper portion of the cylinder 4 through the conduits 5 and 6 and thevalve 7, which initiate to start to lower the ram 2 downwards. When theupper surface of the plunger 3 falls to separate from the lower surfaceof the cylinder 4, the high pressure gas immediately operate to push onthe upper surface of the plunger 3 so that the ram 2 is forced to falldownwards in very high speed to operate its impact forming (forming inFIG. 2, and designated by numeral II in FIG. 7). At this time,simultaneously with the fall of the ram 2 by its reaction the movableframe 10a moves upwards in height H from the normal position or level A,thereafter immediately descends, and further falls down proper amountfrom the normal level A. Thereafter, it returns immediately to thenormal level A. This height H is sufficiently smaller than space Lbetween the upper surface of the movable frame 10a disposed at itsnormal position A and the lowermost end of the rod 14 of the stopperpiston 17, accordingly the movable frame 10a does not contact the rod14. This bound of the movable frame 10a is effected because it issupported by the cushion 26 in a movable state.

While the above mentioned operation is held, since the crank 12 furtherrotate from its lowermost dead point to initiate to raise, the stopperpiston 17 is pressed downwards to its lowermost point (that is, strokeL) by the hydraulic pressure immediately before the supporting member 10contacts with the head 9 of the stem 8 (illustrated by numeral II inFIG. 7). Thus provided, even if the crank 12 raise the ram 2 integral tothe stem 8 through the supporting member 10 immediately thereafter, themovable frame 10a does not move upward together with the ram 2 bypressing through the aforementioned stopper piston rod 14, causing onlythe ram 2 raise so that the metal moulds immediately separate and theimpact formed products is at once able to be removed from the mould byan ejecting operation.

FIG. 3 shows the state that the ram initiates to return upwards to itsinitial uppermost position (designated by numeral III in FIG. 7). Sincethe high pressure gas in the chamber 1 is operated to the ram 2 so as toraise the movable frame 10a when the ram 2 is returned by the crankmechanism to its initial uppermost position, if there is no means suchas stopper means 15, the movable frame 10a move upwards together withthe ram 2, causing the metal moulds 28 does not separate each other.

If the stopper means 15 secured to the fixed frame 10c stop from thefirst the upward movement of the movable frame 10a even if the upwardmotion of the movable frame 10a is adapted to be prevented by a part orstopper means 15 of the fixed frame 100, reaction of the movable frame10a is impossible to be effected in the impact forming operation. Or, ifthe space between the movable frame 10a and the stopper means 15 securedto the fixed frame is predetermined to be provided, the reaction of themovable frame 10a is allowed, however, whilst the stroke from that theram 2 initiates to return upwards to its uppermost position after itsimpact forming operation to that the movable frame 10a raises upwards tocontact with the stopper means secured to the fixed frame 100 is done,the movable frame 10a moves further upwards together with the ram 2,between which the metal mould 28 is held in contact each other.

Therefore, the stopper piston 17 in the stopper means 15 in accordancewith this invention must be laterally movable. That is, the stopperpiston 17 allows the movable frame 10a to operate its reaction upon itsimpact forming operation, and it must be laterally movable up and downin order that it stops the upward movement of the movable frame 10atogether with the ram when the ram 2 returns upwards to its initialuppermost position after its impact forming operation.

While the ram 2 returns, the valve 7 maintains to open, thereby the highpressure gas enclosed in the cylinder 4 of the pressure chamber '1 isflown back through the conduits 5 and 6 and the valve 7 to thechamber 1. When the plunger 3 of the ram 2 is inserted fully upwardsinside the cylinder 4 so as to complete to return the ram 2,

the ram 2 is in a state that it is integral to the movable' frame 10a(ram returned completely in FIG. 3, and desnated by numeral III). Atthis point, since the crank 12 is not yet reached to the initialuppermost position and further the ram 2 continue to raise, from thispoint the ram 2 and the movable frame 10a integrally move upwardsopposite against the hydraulic pressure of the stopper piston 17 furtherin the rested stroke D. Therebetween, the cam 20 is adapted to close soas to shut off the conduits 5 and 6 in order to keep its safe state(crank in its upper-most position in FIG. 4, and illustrated by numeralIV in FIG. 6).

Thus, during the stroke D until the crank 12 reaches its uppermostposition, the crank 12 are allowed to raise further in a state that theram 2 holds in its uppermost position. Therebetween, the closureoperation of the valve 7 is positively done. Thereafter, the cranks 12initiate its down stroke. Thus, even if the ram 2 is not held in itsuppermost position, the high pressure gas in the chamber 1 is notpermitted to flow back through the conduits 5 and 6 and the valve 7 soas to effect upon the upper surface of the plunger 3 so that the ram 2may not be operated accidentally to descend downwards.

If the valve 7 is open or is not closed completely immediately after theram 2 reached its initial uppermost position so as to lower thesupporting member 10, the

high pressure of the chamber 1 flown back through the conduits and 6 andthe valve 7 effects to actuate upon the upper surface of the plunger 3so that it initiates to descend the ram 2 accidentally causing itsdangerous operation. In this case, as was described hereinbefore, whenthe supporting member of the ram 2 reciprocates up and down by means ofa mechanical force such as the crank 12, it moves downwards or in such adirection that it separates from the ram 2 immediately after it reachesits initial uppermost position so that it removes the supportingoperation of the ram 2. Accordingly, the valve 7 must be closedimmediately after the supporting member 10 reaches its uppermostposition. If the valve 7 closes before the ram 2 reaches its uppermostposition, the gas enclosed in the cylinder 4 cannot return through theconduits 5 and 6 and the valve 7 to the chamber 1. Furthermore, theplunger 3 of the ram 2 is not yet reached to its uppermost position orits inner uppermost position, accordingly the compression occurs in thecylinder 4 by the plunger 3. Also, if the valve 7 closes after the ram 2arrives at its uppermost position, the gas flown back through theconduits 5 and 6 and the valve 7 initiate to operate accidentally theram 2, since the supporting member 10 initiate to descend before thevalve 7 closes. From the reason described hereinbefore, it will beunderstood by those skilled in the art that it is very important toadapt for the crank 12 to be able to further raise its stroke D evenafter the ram 2 reaches to its uppermost position relative to themovable frame 10a.

When the crank 12 initiates to descend after it reaches its uppermostposition, since the supporting member 10 initiates to descend in a statethat the ram 2 integral to the stem 8 is left from the member 10 withoutany further support the stopper piston 17 tends to descend by thehydraulic pressure applied thereabove, the movable frame 10a falls downtogether with the ram 2 by its weight so as to balance with the cushion26 to stop at the normal position A (frame descended completely in FIG.6, and illustrated by numeral VI in FIG. 7). The crank 12 will furtherdescend, accordingly the supporting member 10 continues to descend,after the movable frame 10A stabilize at its normal position A, thestopper piston 17 is pressed upwards by the hydraulic pressure appliedtherebeneath (illustrated by numeral VI' in FIG. 7), and returns to itsinitial state shown in FIG. 1.

Thus, as was described hereinbefore in the embodiments, hydraulicpressure stopper means comprising the stopper piston 17 and thehydraulic pressure cylinder operates not only as the stopping mechanismfor the movable frame 1011, but to allow it to be cushioning function inthe stroke D after the ram 2 reaches its uppermost position relative tothe movable frame 10a. Such a cushioning function may be separatedtherefrom, and another hydraulic pressure means may be provided for thesame effect of the function.

In FIG. 8, another embodiment for the above-mentioned means to effectseparately the cushioning function is shown in addition to the previousembodiment in the high speed returning impact forming machine in which acushionng mechanism or hydraulic pressure means 29 comprising a cylinder30 and a piston 31 is adapted to be inserted between the connecting rod13 and the supporting member 10 for the stem 8. That is, when the ram 2returns to its uppermost position the stopper piston 17 effects to stopupwards movement of the movable frame 10a and after the ram 2 reachesits uppermost position relative to the movable frame 10a, in the raisingstroke D of the crank 12 said piston 31 effects to cushion therebetween.In this case the movable frame 100 does not raise upwards, but it isequivalent to the cushioning function against the jacking mechanism.

As was described in detail hereinbefore, this invention eliminates theupward movement of the movable frame together with the raising ramimmediately after the impact forming operation has done in the machineby mere provision of the stopper mechanism so that the relative motionbetween the ram and the movable frame is enabled. Further, it makespossible to separate immediately the impact formed product from themould, and allow the movable frame to operate sufficient reaction uponthe operation. When the ram returns to its uppermost position, evenafter the ram reaches its uppermost position relative to the movableframe, it enables further the cushioning function against the jackingmechanism between which the operation of the valve for communicatingbetween the high pressure chamber and the upper portion of the cylinderfor operating the ram is extremely usefully effected positively andaccurately.

This invention is not limited by providing the stopper means above themovable frame, which means may be disposed in any position or theconstruction of which is not limited by utilizing fluid pressure andmechanical means may be used.

What is claimed is:

1. High speed returning impact forming machine comprising a gas pressurechamber containing high pressure gas, a ram adapted to be actuated at ahigh speed by gas pressure in said chamber, a plunger provided on saidram, a cylinder for receiving said plunger provided on the top wall ofsaid chamber, a valve for communicating the flow of said gas pressurebetween said chamber and said cylinder of each other, conduits forconnecting between the upper portion of said cylinder and said chamber,a stem longitudinally extended upwards from the top of said ram having ahead on the top, a ram supporting member driven laterally for raisingand releasing said ram, means for driving laterally up and down saidmember, means for driving said valve open or close, said means fordriving said valve being operated so that it close immediately aftersaid plunger contacts said cylinder, a movable frame being disposedlaterally movably upward and downwards inside a guide of a fixed frameand supported by a cushion at its lowermost portion, and hydraulicpressure stopper means disposed above said movable frame and secured tothe fixed frame, said stopper means being operated so that when the ramreturns upwards metal moulds separate immediately from each other.

2. High speed returning impact forming machine as set forth in claim 1,in which said stopper means comprise hydraulic pressure cylinderdisposed fixedly downwards to the upper portions of the fixed frame,stopper pistons being inserted to said cylinders respectively, and rodsadapted to be integral to said piston, said rods being projecteddownwards and disposed opposite to the upper surface of said movableframe, thereby enabling to stop said movable frame moving upwards.

3. High speed returning impact forming machine as set forth in claim 1,in which said pistons of said stopper means are adapted to be able tolaterally move upwards and downwards by applying hydraulic pressure fromthe upper or lower portion of said cylinder.

4. High speed returning impact forming machine as set forth in claim 1,in which said stopper means are disposed so that the distance betweenthe lowermost portion of said rods and the uppermost of said movableframe balanced with said cushion is larger than the bounded height ofsaid movable frame from the normal level caused by the reaction of saidram descended.

5. High speed returning impact forming machine as set forth in claim 1,in which said stopper piston of said stopper means is adapted to bedisposed at its lowermost position immediately before said supportingmember initiates to contact said head of said stem on the Way movingfrom its lowermost position.

6. High speed returning impact forming machine as set forth in claim 1,in which said stopper pistons are disposed so that when said plunger ofsaid ram reaches its uppermost position in said cylinder said crankenable to raise further integrally with said supporting member togetherwith said ram on opposing to the hydraulic pressure in upper portion ofsaid stopper means in its rested stroke.

7. High speed returning impact forming machine as set forth in claim 1,in which hydraulic pressure means are disposed between on the top ofsaid means for driving said member and the lowermost portion of saidmember, said hydraulic means being so operated that said means fordriving said member further move upwards to the top during apredetermined time after said ram integral to said member has reachedits uppermost position.

8. High speed returning impact forming machine as set forth in claim 7,in which said hydraulic pressure means comprises a piston provided onthe top of said means for driving said member, a cylinder for receiving1 said piston provided on the lowermost portion of said member, passagesbored longitudinally along with said member and conduits for connectingthe ends of said passages and hydraulic pressure source.

References Cited UNITED STATES PATENTS 3,103,136 9/1963 Bollar 724533,105,414 10/1963 Cvjetkovic 72453 3,158,048 11/1964 Bollar 724533,194,049 7/ 1965 Riemenschneider 72453 3,352,143 11/1967 Bollar 724533,354,693 11/1967 Asari 72453 RICHARD J. HERBST, Primary Examiner.

G. P. CROSBY, Assistant Examiner.

US. Cl. X.R. 72453; 100-269

